Reported herein is a thermally induced dearomative rearrangement of α-(aza-heteroaryl)-α'-prop-2-enyl malonate derivatives, affording 4H-dihydroquinolizine derivatives (21 examples, 26-89%). The rearrangement, assisted by microwave heating, afforded diastereoselective quinolizidine scaffolds, known for their broad biological activities. Experimental results and DFT calculations converge to support a stepwise mechanism initiated by intramolecular 1,4-addition of pyridine nitrogen to the activated acrylate moiety followed by selective ester transfer.
Locquet et al. (Thu,) studied this question.